1. Field of the Invention
The present invention relates to systems, processes, and methods for making cheese products. More particularly, the present invention relates to a system and method for making cheese products which are enhanced to have a particular characteristic, such as increased yield, recovery of whey cream, desired protein content, water content, flavor, resistance to spoilage, accelerated ripening, or reduced, light, low fat, or fat free cheese, and Instant Quick Frozen Pizza cheese.
2. State of the Art
The making of cheese is generally a labor-intensive process that requires large quantities of milk to develop any of the many popular varieties. Typically, cheese yields range from 6% to 12% depending upon the variety and moisture content of cheese. The remainder of the milk forms by-products. Whey is the single largest product from the milk during the cheesemaking process and, prior to the present invention, has often been viewed as a negative by-product.
Numerous steps are required to turn milk into cheese having the desired characteristics of color, body, texture and organoleptic properties. Many of these steps are highly labor intensive and limit the speed and cost at which cheese can be produced. Additionally, success or failure in the market place is often determined by a company""s ability to create cheese with the proper body, texture and organoleptic properties at the most competitive price. Because of the highly competitive nature of the cheese making industry, price differences of less than one cent per pound can provide significant advantages in the market place.
One significant concern that must be addressed for a cheese maker to be profitable is disposal of the by-products created during the cheese making process. For example, the formation of some types of cheese requires that the cheese be soaked in a brine solution. The brine solution quickly becomes contaminated with the cheese and the resulting breakdown products, primary free fatty acids and proteins. The resulting breakdown products of the cheese promote bacterial growth in the brine, which leads to contamination of the finished cheese. Further, the salt brine dissolves some of the cheese that leads to loss of yield.
Once the bacterial growth has reached certain levels, the contaminated brine solution must be discarded. The contaminated brine solution, however, must be specially handled in such a manner that it will not contaminate water supplies and or cause other environmental damage. Disposal of the brine solution is currently a major problem in the mozzarella industry and has forced some plants to close due to environmental concerns. Other cheeses that typically are brined include Brick, Romano, Parmesan, Blue, Swiss, etc. Disposal of the brine solution causes considerable problems in these portions of the cheese industry as well.
Another significant concern that must be addressed by nearly all cheese makers is disposal of cheese whey that is released during the cheese making process. As mentioned above, cheese whey is the largest product of the cheese making process. Cheese whey is a watery substance that contains large amounts of whey protein and lactose, which cannot be coagulated out of milk by typical coagulating enzymes or acid precipitants. Cheese whey contains approximately 0.9 percent whey protein and 5 percent lactose. About 25 percent of the total protein in milk is whey protein. Thus, disposal of cheese whey can be a significant problem.
Numerous attempts have been made to reintroduce the whey protein into cheese to eliminate disposal concerns and to enhance the protein content of the cheese and the yield. For example, in accordance with one method, whey protein extracted from one batch of milk during the cheese making process is returned to a subsequent batch of milk in an attempt to coagulate the whey protein with the cheese curds. Such attempts, however, have been relatively unsuccessful. Typically no more than about 18 percent of the whey protein reintroduced into the milk will precipitate out with the cheese curds. Several methods and procedures have been developed and patented over the years that primary utilize denatured whey protein in combination with caseins to form co-precipitates that have a propensity to precipitate out of the vat milk with the cheese curd. The efficiency of these processes and the effect upon the finished cheese is varied and none has achieved desired levels of whey precipitation. Thus, the remaining whey protein must be used for other purposes or disposed of in an appropriate manner.
One major problem with denaturing whey protein to the degree that it needs to be in order to precipitate out with the casein and fat is the whey proteins"" effect upon the body and texture of the finished cheese. The denaturing process itself changes the whey protein conformation such that it materially affects the body and texture of the finished cheese. The physical chemistry involved in the coagulation of milk to form cheese is very complex and not fully understood. Anything from simple vibration to the type denatured whey protein will materially affect the coagulation and hence, the yield, as well as the body and texture of the finished cheese.
One solution to handling the cheese whey has been the making of alternate products. Ultra filtration has been tried and has been successful for making a pre-cheese that has been set with rennet to make cheese. Some cheeses have been made this way for over twenty years with market acceptance in various parts of the world. However, when Ultra filtration was used to make mozzarella in the United States, the resulting cheese would not melt and stretch satisfactorily. Thus, the ability to use the cheese whey to develop other cheese products or increase yield has been limited.
The whey protein which cannot be used within the cheese making process must be dried or otherwise processed to remove it from the liquid whey. A commercial whey drier typically costs between about 5 and 10 million U.S. dollars and consumes a significant amount of space and energy. Numerous other systems are also available for separating the whey protein from liquid cheese whey. For example, various mechanisms for separating the whey from the liquid are disclosed in U.S. Pat. Nos. 3,642,492; 3,640,996; 3,873,751; 4,297,382; 4,497,836 and 4,617,861, to name a few. Of course, several such systems may be used in conjunction with one another to separate and dry the whey protein.
Disposal of the whey is difficult because the high protein concentration and high BOD can quickly contaminate wells and local streams and rivers. The high protein concentration can cause algae blooms in surface waters, and can render ground water unusable for many purposes.
While the high protein concentration of the whey has been found to be desirable for use in health drinks and other nutritional snacks, the market are generally insufficient to keep whey protein prices higher than the cost of production. This is due, in part, to the properties of the whey protein. Thus, while cheese solids in mozzarella are currently worth about $2.40-$3.60 (U.S.) per pound, the whey protein sells for about $0.58 (U.S.) per pound. When the costs associated with drying and handling are figured in, the cheese producer usually sells its whey protein at a loss.
In response to this ongoing problem, numerous new products have been developed to utilize the whey protein. For example, U.S. Pat. Nos. 3,642,492 and 3,873,751 teach a method for making a simulated skim milk. Likewise, U.S. Pat. Nos. 4,161,552 and 4,259,363 disclose the use of whey solids in place of non-fat dry milk for making comminuted meats. These products, however, have not been sufficiently successful to create a significant market for the whey protein.
Other companies have specially engineered proteins that are synthesized from the whey proteins. While such specialty proteins make the handling of whey protein profitable, there is a limited demand for such proteins, and the proprietary rights of certain companies limit who may produce the products.
Thus, there is a need for a system that can more effectively utilize whey protein obtained during the cheese making process to thereby increase profitability. Such a system should have little or no negative environmental impacts and should be relatively easy to use. Thus, with the cheese market at $1.80 (U.S) per pound, the most profitable return for whey protein would be to return it to the cheese thereby increasing yield.
In addition to brine and whey protein, ten percent of the butterfat is lost to the whey and is recovered as whey cream. Whey cream is sold as a by-product at a low return. This process returns the whey to the curd for a high return and increased yield.
In addition to brine, whey protein and whey cream, there are several other concerns that limit the profitability of cheese makers. For example, spoilage of cheese is a common problem. As cheese sits in warehouses or on store shelves, mold and/or bacteria can grow on the cheese, thereby making the cheese unfit for consumption. This is especially problematic for fresh cheeses.
It is well known that there are several acids and metabolics of bacteria that interfere with growth of bacteria and the like on cheeses. These substances, include, but are not limited to nisin, MICROGUARD and MICROGUARD PLUS (available from Rhoda, Madison, Wis.), NIPISAN (available from Aplin and Barrett, Beaminster, England), and the ALTA series (produced by Quest International of Hoffman Estates, Illinois). These items are typically referred to as probotic metabolites. By interfering with bacterial growth, the probotic metabolites serve as a shelf life extender and decrease losses due to spoilage. While probotics have been used in other food products, there has been a general inability to effectively add probotics to cheese products. This is because the probotics interfere with the growth of the cheese culture. Currently, the probotics are applied to the surface of the cheese, but no mechanism has been found to infiltrate the cheese to provide consistent improvement in shelf life. Thus, there is a need for a method of manufacturing cheese by which probotics and the like can be added to the cheese products to effectively reduce spoilage.
In addition to providing a mechanism for reintroduction of whey protein into cheese to reduce or eliminate disposal concerns, the method of the present invention enables the probotics to be added after the culture has preformed its necessary functions. Thus, the probotics afford the ability to prevent further culture growth along with the prevention of other growth by spoilage or contaminating bacteria. Contaminating bacteria typically produce off flavors or texture defects such as gassing in cheese. The specially introduced probotics, however, can substantially reduce or eliminate such concerns.
Related to the concern of spoilage is the need for refrigeration. In order to market cheese, the cheese must be maintained at a sufficiently low temperature to prevent spoiling. The costs of electricity alone can be substantial when dealing with high volumes. However, by using probotics in accordance with the present invention, the requirement that cheese be refrigerated can be reduced or even eliminated. If the levels of probotics are sufficient, the only need for refrigeration of cheese comes from the need to maintain the cheese below high temperatures (such as about 90 degrees Fahrenheit) wherein the fats in the cheese start xe2x80x9coiling offxe2x80x9d.
Yet another problem which has faced the cheese making industry for many years is the desire of many people to purchase low fat or fat free cheeses which have substantially the same body, texture and organoleptic properties as the tradition product. The protein matrix formed by casein in cheese entraps both the moisture and fat globules. The physical structure of the fat prevents the protein from contracting into a hard brittle matrix. However, when fat is removed from cheese, the protein matrix continues to contract during aging and the resulting body and texture does not resemble the fat containing cheese.
In addition to the ability to reintroduce whey protein and add probotics, the present invention allows the infusion of materials into the protein matrix such that the protein web like structure will not contract. If the infused particles resemble the mouth feel and lubricity of fat, then the cheese texture will resemble that of the original cheese product. The fat molecule, however, is critical both to the texture and taste of the cheese product. Currently, most reduced fat cheeses are rubbery and tough and lack the taste of traditional cheese. In light of the increasing demand for low fat foods, it is desirable to develop a system for enhancing cheese which enables the production of low fat cheese which has the body, texture and organoleptic properties of regular cheese.
Still another challenge faced by the cheese industry is the limited ability to produce cheese having selected flavors. Currently there is widespread demand for food products which are both high in nutrition and which have a pleasing flavor. Many of the top selling treats are fruit flavored snacks in which fruit extracts are used. While attempts have been made at developing novelty cheeses having a variety of nontraditional flavors, such have been unsuccessful because cheese will not normally adopt flavors or colors in a consistent manner. Thus, while a flavor may be added to cheese, it may be much stronger in some areas of the cheese than in other areas. This invention allows the incorporation of fruit solids, flavors, and sweeteners into the cheese mass in a consistent manner to thereby facilitate the use of a variety of flavors.
In addition to novelty flavors, there are many cheeses that require prolonged aging or ripening to obtain the desired flavor. Traditionally, penetration of the cheese by the enzymes that ripen the cheese has taken months. Current technology allows the cheese maker to accelerate the ripening of cheese by incorporating the cheese with known enzymes while the cheese is on the finishing table. The enzymes, however, are extremely expensive (i.e. up to seven hundred dollars U.S. per pound) and 25 to 40 percent of the enzymes are lost to the whey. Additionally, uniform distribution of the cheese with the enzymes remains a significant problem. Conversely, defects known as modeling are common with the use of enzymes in the above manner.
A closely related problem with accelerated ripening of cheese is the inability to control the aging process. Once an enzyme has been introduced, the aging/flavor change of the cheese continues. Thus, the cheese continues to age the longer it is on the shelf and eventually becomes too strong for most consumers. Thus, there is a need for a method by which improved control is provided for accelerated aging. The present invention provides the cheese maker with improved control of the accelerated ripening technique on several fronts. First, the method of the present invention allows for improved penetration of the cheese curds with the enzyme used for accelerated ripening. Second, the method of the present invention allows for the same day production of aged cheese by the use of a cheese/enzyme concentrate that is prepared independent of the cheese. Third, in accordance with the principles of the present invention, it has been found that selective inactivation of the enzyme used for accelerated ripening can be used to inhibit over ripening of cheese products made by an accelerated ripening method.
Still yet another problem associated with the manufacture of cheeses is the labor involved in the production. This is especially true for cheeses that are formed, cooled and then grated or shredded into small pieces of cheese. Such is common for cheese that is used by commercial establishments on pizzas. The small cheese particles melt more rapidly on the pizza and prevent excessive browning. However, to form Pizza cheese, the cheese curds are usually formed in the pasta filata process, passed through brine solution to cool, and then grated or shredded. A significant saving could be achieved by reducing the amount of labor, equipment, and waste to form the Pizza cheese particles. This invention only uses one piece of equipment and one process to produce Instant Quick Frozen (IQF) Pizza cheese. Furthermore, the improved Pizza cheese has increased yield and maintains the excellent and controllable properties over the entire shelf life of the cheese.
It is an object of the present invention to provide a system and a system and method for manufacturing an enhanced cheese product having a desired characteristics.
It is an object of the one aspect of the present invention to provide a system and method for reintroducing whey protein concentrate into cheese curds so as to increase the amount of cheese to be produced by a given quantity of milk.
It is an object of the one aspect of the present invention to provide a system and method for reintroducing whey cream into cheese curds so as to increase the amount of cheese to be produced by a given quantity of milk.
It is an object of one aspect of the present invention to introduce whey protein into cheese curds to enhance the protein content of the curds.
It is an object of another aspect of the present invention to provide a system and method for enhancing the shelf life of cheese products and/or reducing the need for refrigeration.
It is an object of another aspect of the present invention to provide a system and method for production of low fat or nonfat cheese having improved body, texture and organoleptic properties.
It is an object of yet another aspect of the present invention to prove an improved system and method for adding flavorings and/or colorings to cheese.
In is an object of still another aspect of the present invention to provide an improved system and method for accelerated aging of cheese products.
It is an object of still yet another aspect of the present invention to provide an improved system and method for controlling the aging process of cheese products.
It is another object of the present invention to provide an improved system for making mozzarella cheese, Pizza cheese and other pasta filata cheeses.
The above and other objects of the invention not specifically enumerated are realized in specific illustrated embodiments of a system and method for producing an enhanced cheese product. Milk is processed so as to produce cheese curds. An enhancing agent is then added to the cheese curds and the two are mixed together and subjected to negative pressure. The negative pressure causes the cheese curds to draw in the enhancing agent. The enhanced cheese curds are then processed in a conventional manner or other manner to form blocks of cheese or some other desired cheese product. Typically, this process is referred to as knitting.
In accordance with one aspect of the present invention, the enhancing agent is whey protein. Preferably, the whey protein is in the form of an eighty-percent whey protein concentrate, although other forms or concentrations may also be used. The whey protein is mixed with the cheese curds and subjected to negative pressure. This causes the whey protein to be absorbed into the cheese curds. It has been found that a substantial part, if not the entire amount, of whey protein produced as a by-product of a batch of cheese can be reintroduced into the cheese curds. Thus, the disposal problem of the whey protein is virtually eliminated. Additionally, the resulting cheese product has an equal or superior taste to traditional cheese. The cheese also has a higher protein concentration, lower fat concentration and a higher water concentration, making it more nutritious. Furthermore, utilizing the process of the present invention results in approximately 25 percent more cheese product per gallon of milk than is produced in accordance with the traditional methods of making cheese. Thus, the cheese maker is able to produce cheese that is healthier to consume and which lowers the cost per pound significantly.
In accordance with another aspect of the present invention, the whey portion of the mixture can be provided in a variety of different ways. For example, one can select cheese whey and lower the pH by adding an acidulating agent, such as vinegar or citric acid. The mixture is then heated to about 190 degrees (typically by direct steam injection) and the whey protein precipitate that floats to the top is recovered. The whey protein precipitate is then subjected to high sheer (i.e. mixing or high-pressure homogenization) to reduce precipitate particle size. Once the particle size is below a defined size (i.e. about 8 microns, and preferably of a mean size of 1 micron), the whey protein is added to the cheese curds and mixed under negative pressure.
In accordance with another aspect of the present invention, it has been learned that an enhancing agent in the form of a preserving agent, such as a probotic, can be mixed with the cheese curds (and whey protein concentrate if desired) and subjected to negative pressure. The negative pressure causes the cheese curds to absorb the preserving agent. Because the preserving agent is absorbed by the cheese curds, the resulting cheese product is less susceptible to spoiling and the shelf life of the cheese product is lengthened. Additionally, the use of appropriate amounts of probotics can also reduce or eliminate the need to refrigerate the cheese. Thus, probotics can be used to make cheese which only requires sufficient refrigeration to avoid oiling off in extremely warm weather.
In accordance with another aspect of the present invention, it has been learned that an enhancing agent in the form of a fat substitute can be mixed with the cheese curds. The mixture can then be subjected to negative pressure in such a manner that the fat substitute infiltrates the cheese curd and produces a reduced fat cheese having similar body, texture and organoleptic properties as traditional cheese. If desired, the cheese curd can be processed prior to mixture to form low fat or nonfat cheese curds. By adding the fat substitute to the low fat or nonfat cheese curds, the cheese manufacturer is able to provide a cheese which has significantly less fat (or even no fat) while maintaining the body, texture and organoleptic properties of regular cheese.
In accordance with still yet another aspect of the present invention, it has been learned that flavorings and/or colorings can be mixed with cheese curds and subjected to negative pressure in such a manner that the flavoring and/or coloring is spread through cheese product. Thus, cheeses of novelty flavors such as strawberry, banana, chocolate, etc. can be produced with a significant improvement in flavor consistency. For snack food type cheeses, such as string mozzarella, the ability to add novelty flavors enables the sale of the cheese product at candy pricesxe2x80x94prices well above those traditionally charged for cheese.
In accordance with still yet another aspect of the present invention, enzymes that are used to accelerate the ripening of cheeses are mixed with the cheese curds. Because the enzymes are absorbed by the cheese curds, the infiltration of the cheese curds is more consistent and considerably less enzyme must be used to provide the desired agingxe2x80x94further reducing costs.
In accordance with another aspect of the present invention, the enzymes can be placed in a small amount of cheese and then processed in such a manner as to optimize the catalytic effect of the enzyme to thereby obtain an aged cheese product having a very concentrated flavor in a very short amount of time. The aged cheese product or cheese/enzyme concentrate is then mixed with cheese curds to impart the desired flavor to a larger amount of cheese. By optimizing the enzyme""s catalytic effect to form a cheese/enzyme concentrate and then mixing the cheese product with cheese curds, a desired flavor can be achieved within a small fraction of the time traditionally required for the flavor to develop in the cheese.
In accordance with still another aspect of the present invention, the enzyme which is used to promote accelerated aging of the cheese may be controlled by applying heat or some other controller to inactivate the enzyme once a desired aging has been achieved. For example, if a cheese/enzyme concentrate is processed to provide the flavor of a cheese that has been aged for two years, the concentrated cheese product can be subjected to sufficient heat to substantially terminate further propagation of the enzyme. Because the enzyme has been inactivated, the cheese product formed by mixing the cheese curds and the cheese/enzyme concentrate under negative pressure continues to age at a much slower rate than normal. Thus, the cheese product will have a much greater shelf life as being aged xe2x80x9ctwo yearsxe2x80x9d, while a conventionally aged cheese will continue to age and will continue to become sharper, etc. Thus, a very uniform aged cheese can be produced in a very short amount of time.
Still another aspect of the present invention is the infusion of hydrocolloids, starch, and/or milk protein derived stabilizers. These ingredients or any other water controlling agents can be infused into the curd to prevent syneresis. Syneresis of whey off is caused by the presence of additional water beyond the ability of the casein and/or whey protein binding capacity. Hence, the addition of hydrocolloids or proteins will allow for the incorporation of greater moisturexe2x80x94thereby enhancing the quality of low fat or nonfat cheeses. Furthermore, additional bound moisture improves the meltability of cheeses such as mozzarella.
Still yet another aspect of the present invention relates to the preparation of small particles of cheese, such as a grated or shredded Pizza cheese, while reducing labor costs and environmental hazards. Forming the cheese curds into blocks and floating the block through a brine solution typically forms Pizza cheese. The block is cooled and allowed to age for a sufficient period to develop a slight salt taste to penetrate the cheese. The sodium ion replaces the calcium ion bound to the protein and allows the pasta filata cheese to produce the typical stretch and smooth homogenous melt associated with this cheese. The cheese is then grated or shredded into small particles and shipped to pizzerias and the like.
The present invention avoids the labor intensity and environmental problems of the method discussed above by infusing salt or a salt solution into the cheese curds. The cheese curds are then quick frozen by carbon dioxide or nitrogen injection and are ready for shipment. The curds have a similar flavor to those produced by the conventional process while substantially reducing handling, loses of cheese solids to cooker water and brine, labor costs, and environmental concerns such as brine disposal. The cheese curds may also be enhanced to increase yield, provide other characteristics such as flavor or color, or provided with melting enhancers such as phosphates or citrates, and body builders or texturizers such as starch, and enzymes to enhance stretch, etc. Thus, this invention provides a one step process for manufacturing an improved pasta filata cheese with substantially improved yield and performance characteristics. The improved performance characteristics will remain stable for the entire shelf life of the cheese. Further, performance characteristics can be tailored to a specific end use and will not change during the shelf life of the cheese.